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LaurieWired

@lauriewired • 161,181 subscribers

researcher @google; serial complexity unpacker; https://t.co/Vl1seeNgYK ex @ msft & aerospace

Shorts

You’ve heard of DRAM, HBM, probably SRAM, but RDRAM…now that was a weird one. Famously used in the Sony PS2, its RDRAM had ~3x the bandwidth of your typical high end PC. If you want more memory bandwidth in a dense die, there’s (roughly) two things you can do. You can *add* many more wires (wide+close, like hbm). Or, you can make the wires *faster* and use less of them (narrow). Rambus, the creator of RDRAM, took the second bet. It was quite contrarian, but garnered some attention from Intel as well. The main issue, among others, is that RDRAM was expensive, AND high latency. For typical PC-style workloads, random access latency dominates, so it was a tough sell. Although the PS2 was a roaring success (high-bw streaming workloads made sense), it barely lasted ~3 years in the PC market. Like many ideas, Rambus+RDRAM was arguably just way, way too early. Today, CXL memory uses many of the same initial principles! If you think about a pin-efficient, high speed link, over longer distances…well, that’s kinda just CXL. Funnily enough, Rambus still exists, and is heavily involved in CXL memory controller IP these days!

You’ve heard of DRAM, HBM, probably SRAM, but RDRAM…now that was a weird one. Famously used in the Sony PS2, its RDRAM had ~3x the bandwidth of your typical high end PC. If you want more memory bandwidth in a dense die, there’s (roughly) two things you can do. You can add many more wires (wide+close, like hbm). Or, you can make the wires faster and use less of them (narrow). Rambus, the creator of RDRAM, took the second bet. It was quite contrarian, but garnered some attention from Intel as well. The main issue, among others, is that RDRAM was expensive, AND high latency. For typical PC-style workloads, random access latency dominates, so it was a tough sell. Although the PS2 was a roaring success (high-bw streaming workloads made sense), it barely lasted ~3 years in the PC market. Like many ideas, Rambus+RDRAM was arguably just way, way too early. Today, CXL memory uses many of the same initial principles! If you think about a pin-efficient, high speed link, over longer distances…well, that’s kinda just CXL. Funnily enough, Rambus still exists, and is heavily involved in CXL memory controller IP these days!

217,729 просмотров

We take randomness for granted. Early PRNGs were BAD. Thousands of scientific papers used to rely on RANDU, created by IBM in the 1960s. In 1D space, it looks ok! Map in 3D…you start to see the issues. Now, there *was* a better solution...but it would cost you.

We take randomness for granted. Early PRNGs were BAD. Thousands of scientific papers used to rely on RANDU, created by IBM in the 1960s. In 1D space, it looks ok! Map in 3D…you start to see the issues. Now, there was a better solution...but it would cost you.

589,805 просмотров

I think we can salvage it

I think we can salvage it

73,726 просмотров

Every year shopify makes a website tracking the massive surge in compute on black friday. Right now they are tracking ~45+ million Kafka requests per second, and about 88,000 gigabytes of data per minute. (it's also just a really cool website)

Every year shopify makes a website tracking the massive surge in compute on black friday. Right now they are tracking ~45+ million Kafka requests per second, and about 88,000 gigabytes of data per minute. (it's also just a really cool website)

238,069 просмотров

It's hot out there today guys. Don't forget to keep your servers cool with a nice hose-down.

It's hot out there today guys. Don't forget to keep your servers cool with a nice hose-down.

536,529 просмотров

Modern tech tends to focus on “more”. More data. More bandwidth. More compute. The best software engineering happens in the “less” sphere; codec engineering. Listen to this stream with 90% packet loss. The Opus Encoder team is cracked:

Modern tech tends to focus on “more”. More data. More bandwidth. More compute. The best software engineering happens in the “less” sphere; codec engineering. Listen to this stream with 90% packet loss. The Opus Encoder team is cracked:

244,761 просмотров

Sharks love our undersea cables. Some suspect the weak, low-frequency fields attract sharks like distressed fish. Fiber optics are particularly tasty; AT&T expressed no incidents with “old [copper] cables”. In the 80s, telecoms called the incident Jaw's Syndrome.

Sharks love our undersea cables. Some suspect the weak, low-frequency fields attract sharks like distressed fish. Fiber optics are particularly tasty; AT&T expressed no incidents with “old [copper] cables”. In the 80s, telecoms called the incident Jaw's Syndrome.

232,072 просмотров

I promise this relates to RAM (you'll find out in my next video)

I promise this relates to RAM (you'll find out in my next video)

76,534 просмотров

Is your compiler a boy or a MAN? Created by Donald Knuth, it’s a test to check if recursion is implemented properly. Originally written in ALGOL 60, a precursor to C, but can adapt to nearly any language. It really stresses the stack and heap, pushing insane call depths:

Is your compiler a boy or a MAN? Created by Donald Knuth, it’s a test to check if recursion is implemented properly. Originally written in ALGOL 60, a precursor to C, but can adapt to nearly any language. It really stresses the stack and heap, pushing insane call depths:

133,373 просмотров

Absurd as it sounds, with smaller experiments it was completely worth it to: - Buy the book - Open a random page - Mark your starting point with a pen - Hand Type / Punch the data into cards

Absurd as it sounds, with smaller experiments it was completely worth it to: - Buy the book - Open a random page - Mark your starting point with a pen - Hand Type / Punch the data into cards

63,619 просмотров

Wanna know something wild? You can still reproduce a (similar) issue on modern systems. - Open a large file on notepad (not fullscreen) - Select text while scrolling down - Wiggle the mouse and notice the speed difference

Wanna know something wild? You can still reproduce a (similar) issue on modern systems. - Open a large file on notepad (not fullscreen) - Select text while scrolling down - Wiggle the mouse and notice the speed difference

80,326 просмотров

it's not every day you get to touch a Cray-2 supercomputer

it's not every day you get to touch a Cray-2 supercomputer

64,993 просмотров

Of course, that fits nicely in 32-bit hardware. Only a few instructions. Apple put it in CarbonLib, FreeBSD also used it, and for a few decades it was kind of everywhere. A few years later they discovered that 48271 was a little better. Specifically, a bit more even on spectral tests up to 6 dimensions. It’s kind of funny that so few listened. FreeBSD was still using 16807 in rand() all the way until 2021! So if you ever see that constant in disassembled code…well now you know :) (side note: most rand() implementations moved on to other LCGs, or mersenne twisters and such…but it’s arguable that 16807 is still quite ubiquitous!) Original Paper if you’d like to read:

Of course, that fits nicely in 32-bit hardware. Only a few instructions. Apple put it in CarbonLib, FreeBSD also used it, and for a few decades it was kind of everywhere. A few years later they discovered that 48271 was a little better. Specifically, a bit more even on spectral tests up to 6 dimensions. It’s kind of funny that so few listened. FreeBSD was still using 16807 in rand() all the way until 2021! So if you ever see that constant in disassembled code…well now you know :) (side note: most rand() implementations moved on to other LCGs, or mersenne twisters and such…but it’s arguable that 16807 is still quite ubiquitous!) Original Paper if you’d like to read:

21,874 просмотров

This pokemon clone is stored inside a font. Yes, an *actual* font; think Times New Roman. As expected, it's playable anywhere you use fonts. A text document, code editor, etc. The full game takes about ~20 minutes to play, an hour if you find all the secrets. But how?

This pokemon clone is stored inside a font. Yes, an actual font; think Times New Roman. As expected, it's playable anywhere you use fonts. A text document, code editor, etc. The full game takes about ~20 minutes to play, an hour if you find all the secrets. But how?

46,087 просмотров

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someone built a Linux CPU scheduler that makes scheduling decisions based on planetary positions and zodiac signs it actually works haha:

someone built a Linux CPU scheduler that makes scheduling decisions based on planetary positions and zodiac signs it actually works haha:

1,658,954 просмотров • 8 месяцев назад

Modern DRAM is based on a brilliant design from IBM. But, we're still paying for a latency penalty that's existed since the 60s! In this video, I'm introducing my research project (Tailslayer) that immensely reduces p99.99 latency on traditional RAM! By implementing a hedged read strategy taking advantage of (undocumented!) channel scrambling offsets, I've gotten as much as 15x reductions in tail latency. The technique works across Intel, AMD, Graviton, DDR4, DDR5, x86, ARM, you name it. Check out the C++ lib I wrote, watch the video, and try it yourself!

Modern DRAM is based on a brilliant design from IBM. But, we're still paying for a latency penalty that's existed since the 60s! In this video, I'm introducing my research project (Tailslayer) that immensely reduces p99.99 latency on traditional RAM! By implementing a hedged read strategy taking advantage of (undocumented!) channel scrambling offsets, I've gotten as much as 15x reductions in tail latency. The technique works across Intel, AMD, Graviton, DDR4, DDR5, x86, ARM, you name it. Check out the C++ lib I wrote, watch the video, and try it yourself!

865,906 просмотров • 6 месяцев назад

You play doom with a CPU. I play doom with CPU usage. we are not the same

You play doom with a CPU. I play doom with CPU usage. we are not the same

3,746,034 просмотров • 2 лет назад

Programming Isn't Math, It's Linguistics. Compilers and Humans have the same problem. We're all terrible at understanding each other. Join me for some formal language theory, a lot of C++, and some "recreational" insults.

Programming Isn't Math, It's Linguistics. Compilers and Humans have the same problem. We're all terrible at understanding each other. Join me for some formal language theory, a lot of C++, and some "recreational" insults.

984,816 просмотров • 11 месяцев назад

This is gonna make Rust programmers angry. Reflection is one of the most powerful concepts in Computer Science. Unfortunately, not every programming language is blessed enough to have it. Timestamps: 00:00 Powerful Computers have No Security 03:07 Reverse Engineering is Program Surgery 04:55 The first .COM in History 06:56 The Least Private OS Ever Created 09:33 Rebooting, Never? 12:41 Reflection Tier List Ranking 16:13 C++ is getting COOL 18:22 Rust is…Rough 20:13 God-Tier Reflection 22:27 Blessing C++ with…Metadata? 26:44 Rebelling against the Machine

This is gonna make Rust programmers angry. Reflection is one of the most powerful concepts in Computer Science. Unfortunately, not every programming language is blessed enough to have it. Timestamps: 00:00 Powerful Computers have No Security 03:07 Reverse Engineering is Program Surgery 04:55 The first .COM in History 06:56 The Least Private OS Ever Created 09:33 Rebooting, Never? 12:41 Reflection Tier List Ranking 16:13 C++ is getting COOL 18:22 Rust is…Rough 20:13 God-Tier Reflection 22:27 Blessing C++ with…Metadata? 26:44 Rebelling against the Machine

192,621 просмотров • 2 месяцев назад

Gen Z doesn't Understand Filesystems. It's not their fault. Apple's early abstraction of mobile data storage has caused...confusion to say the least. But what does the *real* iOS filesystem look like? As a researcher myself; it's kind of insanely complicated:

Gen Z doesn't Understand Filesystems. It's not their fault. Apple's early abstraction of mobile data storage has caused...confusion to say the least. But what does the real iOS filesystem look like? As a researcher myself; it's kind of insanely complicated:

491,025 просмотров • 1 год назад

This...is Programming Like a Fighter Pilot. A single unhandled exception destroyed a $500 million rocket in seconds. The F-35 wasn't going to make the same mistake. By carefully slicing C++, engineers created one of the strictest coding standards ever written.

This...is Programming Like a Fighter Pilot. A single unhandled exception destroyed a $500 million rocket in seconds. The F-35 wasn't going to make the same mistake. By carefully slicing C++, engineers created one of the strictest coding standards ever written.

377,832 просмотров • 10 месяцев назад

my 2025 predictions in computer science

my 2025 predictions in computer science

628,663 просмотров • 1 год назад

Fading out audio is one of the most CPU-intensive tasks you can possibly do! When numbers get really small, the number of CPU operations can explode 100-fold. In this LaurieWired video, we'll explore the IEEE 754 standard, the fight between Intel and DEC, and more!

Fading out audio is one of the most CPU-intensive tasks you can possibly do! When numbers get really small, the number of CPU operations can explode 100-fold. In this LaurieWired video, we'll explore the IEEE 754 standard, the fight between Intel and DEC, and more!

403,177 просмотров • 1 год назад

Open Source isn't going to help. There's a way to invisibly compromise all software. A perfect, self-replicating "sin" passed down for generations of compilers. It's not just theoretical, and Ken Thompson showed us how.

Open Source isn't going to help. There's a way to invisibly compromise all software. A perfect, self-replicating "sin" passed down for generations of compilers. It's not just theoretical, and Ken Thompson showed us how.

264,920 просмотров • 1 год назад

having too much fun with my next video

having too much fun with my next video

59,875 просмотров • 2 месяцев назад

I love C++. It's the ultimate computer virus. Sometimes, Worse Is Better, New Jersey beats out MIT, and the dirt path always wins. The ghosts of these decisions still affect every operating system we use today! 00:00 The Dirt Path 01:00 A Third-Rate Computer Scientist 03:17 MIT vs New Jersey 05:49 The 100% Correctness Deathtrap 08:24 C++, the Ultimate Virus

I love C++. It's the ultimate computer virus. Sometimes, Worse Is Better, New Jersey beats out MIT, and the dirt path always wins. The ghosts of these decisions still affect every operating system we use today! 00:00 The Dirt Path 01:00 A Third-Rate Computer Scientist 03:17 MIT vs New Jersey 05:49 The 100% Correctness Deathtrap 08:24 C++, the Ultimate Virus

96,727 просмотров • 4 месяцев назад

Telephone Hold music sounds really bad. Mostly because it’s mapping complex instruments to a human throat. Many phone lines these days use CELP, Code-Excited Linear Prediction algorithms. Music breaks down in weird ways when you turn a piano into…speech.

Telephone Hold music sounds really bad. Mostly because it’s mapping complex instruments to a human throat. Many phone lines these days use CELP, Code-Excited Linear Prediction algorithms. Music breaks down in weird ways when you turn a piano into…speech.

133,686 просмотров • 7 месяцев назад

Just built an MCP for Ghidra. Now basically any LLM (Claude, Gemini, local...) can Reverse Engineer malware for you. With the right prompting, it automates a *ton* of tedious tasks. One-shot markups of entire binaries with just a click. Open source, on Github now.

Just built an MCP for Ghidra. Now basically any LLM (Claude, Gemini, local...) can Reverse Engineer malware for you. With the right prompting, it automates a ton of tedious tasks. One-shot markups of entire binaries with just a click. Open source, on Github now.

286,621 просмотров • 1 год назад

ignore the rumors, computer science is still cool here's my predictions for 2026

ignore the rumors, computer science is still cool here's my predictions for 2026

133,876 просмотров • 8 месяцев назад

Merry Christmas everyone!

Merry Christmas everyone!

159,223 просмотров • 9 месяцев назад

$What happens if we can't make another CPU...ever? How long would datacenters last? Does the Internet start to fracture? Of course, it's a hypothetical thought experiment. But it's interesting to think about:$

What happens if we can't make another CPU...ever? How long would datacenters last? Does the Internet start to fracture? Of course, it's a hypothetical thought experiment. But it's interesting to think about:

200,919 просмотров • 1 год назад

One of the best glimpses of chip fabrication comes from a music video. Such Great Heights from The Postal Service has some incredibly rare footage of wafer handling in Skywork’s RF power-amplifier fab. Filming inside (real) cleanrooms almost never happens.

One of the best glimpses of chip fabrication comes from a music video. Such Great Heights from The Postal Service has some incredibly rare footage of wafer handling in Skywork’s RF power-amplifier fab. Filming inside (real) cleanrooms almost never happens.

160,785 просмотров • 10 месяцев назад

This music video can crash your computer. It even has its own CVE number (CVE-2022-38392). Janet Jackson’s “Rhythm Nation” contains specific resonant frequencies that cause errors on certain 5400rpm hard drives. Play at your own risk.

This music video can crash your computer. It even has its own CVE number (CVE-2022-38392). Janet Jackson’s “Rhythm Nation” contains specific resonant frequencies that cause errors on certain 5400rpm hard drives. Play at your own risk.

216,956 просмотров • 1 год назад

can you guess which one is me? (hint I'm always the shortest)

can you guess which one is me? (hint I'm always the shortest)

113,079 просмотров • 8 месяцев назад